1. Field of the Invention
The present invention relates to a computer numerically controlled (CNC) pin grinder gauging system for insuring that a plurality of crankshafts, camshafts or similar shafts and workpieces are properly ground.
2. Description of the Prior Art
The control of the workpiece size which have been ground by grinding machines has traditionally been accomplished by the accurate control of the axis position of the grinding wheel, an in-process gauging system or feedback from a post process gauge. Of these three methods, in-process gauging to control the grinding wheelfeed motion has traditionally been the most accurate, since it directly measures the dimensions of the workpiece being ground and eliminates the need for the machine control to compensate for thermal changes, wheel wear, machine geometry errors, and other process variables.
U.S. Pat. No. 4,637,144 issued to Schemel is typical of these in-process gauging tools. This patent monitors the diameters of crankpins during treatment in grinding machines and includes a guide 6 having a detector 4 and two sensors 3. These sensors are in the form of elongated arms or fingers with edges 5 which must be maintained in continuous contact with the peripheral surface 1B of a crankpin 1 while the axis 1A orbits or circulates along a path P. However, with the advent of precision grinding processes for parts which are not round, such as cams, and for round parts which are ground while being rotated on an axis other than their geometric center, new problems are introduced for accurately controlling the workpiece size.
The present invention describes a process and apparatus which would combine the elements of post-process gauging and in-process gauging to control the workpiece size to the degree necessary for the production of automotive crankshafts and camshafts.